Following an impressive hat-trick in Real Madrid's 4-1 win over Sevilla, Cristiano Ronaldo revealed the most enjoyable period of his career so far was spent at Manchester United.

Ronaldo and his Madrid team-mates will take on United in the first leg of their Champions League round of 16 tie next week. The forward, meanwhile, netted his 20th treble since moving to the Santiago Bernabeu in 2009 on Saturday evening, taking his season tally to 24 goals.

In an interview published in The Sun newspaper shortly after the completion of the thrashing, Ronaldo reflected on his time at Old Trafford with fondness.

"Yes Manchester was a very good cycle for me," Ronaldo told The Sun. "I won everything there. It was a fantastic part of my life there.

"And maybe it was the time I enjoyed my football the most because I was so young. To be at Manchester United - one of the biggest clubs in the world - at just 18. It was a dream.

"And to play alongside those players you had only seen before on television - maybe that's why I feel I enjoyed it there the most.

"I'm not saying I don't enjoy it here in Madrid - I do. But I'm older now, more mature. I'm not a dreamer any more like I was when I was young.

"I'm 28 now so I'm not at the beginning any more. I'm middle-aged!"

Ronaldo has scored more than a goal per game since joining Real on an £80-million transfer, and the Portugal international believes he has improved his all-round contribution following his La Liga switch.

"The statistics have changed because I am more mature and I have learned some things.

"With that maturity you actually do more things for the team rather than for yourself. But I still try to score as many goals as I can although I also try to give a lot of assists.

"You also have to realise that the football here is different, the team is different. Many things here are different," he explained.

Not for the first time, Ronaldo also expressed his admiration of United manager Sir Alex Ferguson, who brought him to the Premier League from Sporting Lisbon in 2003.

"I arrived at United aged just 18 years old and he taught me how to grow up properly in the football world. Who better? He has so much experience - 1,000 players have passed through his hands.

"So he knows and appreciates what young players need. And what he taught me was the importance of decision making. How important it is to make the right decisions on the pitch and off it.

"That's why I say he was like a father to me. He taught me everything, he helped me so much, guided me on so many important things.

"That was in football and in life because his influence and interest doesn't stop at the touchlines. He cares about you as an individual. He is a very human person who understands what you want and what you need.

"I remember one day in my first season and we came to Christmas and, of course, there is no winter break in England.

"I asked him: 'Coach can you give me three or four days to go home to Portugal?' And straight away he said: 'OK no problem.'

"He knew I was very important to the team but he also knew at that time I needed my family so much and that was a very important moment for me. I realised he understood and he cared.

"Sometimes when you asked him for something you didn't get an answer instantly. He would say: 'Let me think about it.' And then next day he would give you his answer - yes or no. Even if it was a 'no' there was a reason and an explanation.

"He knows how to treat people well, how to make you happy, how to motivate you. He has that in abundance and it works because it's real - it comes from inside him. So I owe him a lot. That's why I keep in touch and that's why it will be great to see him."